Interlocking knife switches



July 17, 1923 L. C. WESCOAT INTERLOCKING KNIFE SWITCHES Filed Dec. 27. 1919 direction lzetented July 17, 1923.

UNITED STATES PATENT OFFICE.

LEWIS O. WESCOAT, OI ELKHUBST, NEW YOBK,'ASS IGNOB T0 WESTERN ELECTRIC COMPANY, INCORPORATED, 01 NEW YORK, N. Y. A CORPORATION OF NEW YORK..-

INTERLOCKII IG KNIFE SWITCHES.

Application filed December 27, 1919.-. Serial No. 847,801.

- Elmhurst, in the county of Queens, State of New York, have invented certain new and useful Improvements in Interlocking Knife Switches, of which the following is a full, clear, concise, and exact description.

7 Thisinvention relates to electric switches and particularly to interlocking knife switches. I

It is often essential in the operation of electric circuits that a number of switches be operated in a prescribed order. If only ordinary. knife switches are provided for the operation of such a circuit, the intellience of the operator must be'entirely reied upon.

An ob'ect of this invention is to provide means whereby in a group of-knife switches the opening and closing of the individual switches in the group is made to depend on the operational position of other switches in the group, to the end that the switches may be operated only in a definite order.

The invention comprises a combination of knife switches mounted in a group usually side by side on a, panel together with a bar of insulating material provided with one or more shelf-like protuberances or ledges cooperating with the switches. This bar is arranged to slide longitudinally in a rpendicular to the switch blades and paral e1 to the panel. In the constructions illustrated, all but one of the switches in the group, when all are closed, are locked in the closed position and no switch may be opened except in its turn. When all of the switches are open, all or any combination of them can be closed but only in definite orders.

Referring to the drawing, Fig. 1 illustrates one embodiment of-this invention, and Fig. 2 another embodiment. In Fig. 1 are shown four knife switches 1, 2, 3 and 4, a sliding bar of insulating material '5 with led s 6, 7 and 8, and two bearing straps 9 an 10, by means of which the sliding bar 5 is fastened to the panel on which the switches are mounted. The ends of bar 5 are made to fit freely under the bearing straps 9 and 10 so that the bar is free to move in a direction perpendicular to the switch blades except in so far as it is restrained by the latter.

The switches being shown in closed Osition, it will be seen that on account 0 the bar 5 butting against the blades of switch 4, it cannot be moved to the right until 1 switch 4 has been opened, and on account of interferences by the ledges 6, 7 and 8, switches 1 2 and 3 are prevented from bein opened. when switch 4 has been opene the bar 5 may be moved to the right a sufficient amount to allow switch 3 to be opened, but until switch 3 has been opened, the bar cannot be moved to theright a. suflicient amount to allow switch 2 to be opened. Likewise, until switch 2 has been opened, switch 1 cannot be opened. It is therefore possible to open all the switches only in the order 4-3- 21, and in the claims, this order of opening is designated by the term invariable order.

Now if it is desired to close all the switches, it will be apparent, upon examination of Fig. 1, that this can be accomplished only in' the order 123--4 and this order is also designated in the claims by the term invariable order and if it is desired to close only a part of the switches, that is some particular combination of them, this must be done in a certain order but this order varies with the combinations. For instance, if it is desired to close the switches 1-34=, they can only be closed in the order 134;, or the combination 1-24 can be closed only in that order. In the claims these latter orders in which the switches can be closed are designated as variable progressive orders. In order to accom lish the above limitation on the operation 0 the switches, it will be seen that the dimension A of ledge 6 has been made greater than the dimension B of ledge 7 and likewise dimension B has been made greater than dimension C of ledge 8.

In Fig. 2 are shown two knife switches 11 and 13, a sliding bar 13 with an overhanging ledge and a bearing strap 14. The only substantial difference involved between the arrangements illustrated in Figs. 1 and 2 is that in the latter the switch 11 is a double throw switch with its fulcrum point 10- cated under the overhanging ledge of the bar 13. In this case switch 11 must be closed in one osition or the other before switch 12 can be closed, and vice versa switch 12 must be open before switch 11 can be opened.

What is claimed is:

1. In combination, a pluralit of switches, a contact blade for each switc and a bar provided with one ,or more overhanging ledges, said bar cooperat ng with said switches to prevent the opening and closing of the entire group of said switches except in an invariable order and to prevent the opening and closin of a plurality less than the total number 0 said switches except in variable pro resive orders.

2. In com ination, a switch panel, a plurality of switches mounted on said panel, a contact blade for each switch, and a bar of insulating material mounted on said panel and arranged to slide longitudinally in a direction perpendicular to the blades of said switches and parallel to said panel, sald bar vided with one or more overhanging edges, each ledge cooperating with one of said switches and the whole combination cooperating to prevent the opening and closing of the entire group of sald switches except in an invariable order and to revent the opening and closing of a plurality less than the total number of said switches except in variable progressive orders.

3. In combination, a plurality of switches, each switch having a contact blade, and a bar provided with one or more overhangmg ledges cooperating with said swltches to pre vent the o ning of said switches except in an invaria le order.

4. In combination, two switches, each having a contact blade and a bar provided with an overhanging 1e ge, said bar cooperating with said switches so that one switch cannot be opened until the other switch has been opened and so that said second mentioned switch cannot be closed until said first mentioned switch has been closed.

5. In combination, two switches, each having a contact blade, and a bar of insulating material provided with an overhanging ledge and arranged to slide longitudinally in a direction perpendicular to the blades of said switches and in a plane parallel to the panel on which said switches are mounted, said bar cooperating with said switches to the end that one switch cannot be 0 ened until the other switch has been opene and that said second mentioned switch cannot be closed until said first mentioned switch has been closed.

-6. In combination, a plurality of switches, each switch having a contact blade, a bar of insulating material cooperating with said switches, a plurality of notches in said bar shaped and positioned to limit the closing of said switches, and an overhanging ledge cooperating with each of said notches to prevent the closing of the entire oup of said switches except in an invarial lfa order.

In witness whereof, I hereunto subscribe my name this 24th day of December A. D.,

LEWIS C. WESCOAT. 

